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Levoit’s Core 400S is a neat and powerful air purifier for fairly large living spaces, with app control and smart features thrown in. It doesn’t offer germicidal UV light and its pollution sensor is a bit basic, but overall it strikes a good balance between price, features and performance.


  • High-volume, efficient air purification
  • App controlled with smart features
  • PM2.5 air quality sensor


  • No ultraviolet sterilisation
  • Pricey filters

Key Features

  • A HEPA 13 air purifier for pretty big roomsThis air purifier is designed for big spaces up to 83 square metres (890 square feet). Its HEPA 13 filter can remove pollen, mould spores and even viruses from the air
  • Smart controlsUse the VeSync app to control settings, view air quality history, create schedules and tweak other settings


Levoit’s 400S air purifier is designed for relatively large rooms. It can change the air in an 83 square metre (m2) space up to twice per hour, which ought to be enough to keep the air fresh in a large kitchen/diner or open plan living area. It’s equipped with a three-stage filter that can remove dust, allergens and even viruses, but there’s no ultraviolet light for additional sterilisation.

This air purifier has a built-in particulate sensor, so it can step up the fan speed if the air quality deteriorates – for example because you’re grilling or frying in the kitchen. It also offers simple controls, enhanced by Wi-Fi connectivity and app support, so you can configure schedules and tweak a few other settings too.

Design and features

  • Fairly attractive design with good controls
  • Air quality sensor
  • Useful and reliable app

If you’ve got a large room, you’ll need a large air purifier. The Core 400S is certainly a step up, but it’s not huge, coming up only slightly higher than the average chair seat. Like many other air purifiers, its cylindrical design combines a large air input and filter chamber in the base with a fan section on top. Levoit’s choice of white and black plastics looks tasteful and modern, if perhaps a bit businessy.

Front view of Core 400S
Image Credit (Trusted Reviews)

In the middle of this purifier’s black air output there’s a circular control panel, with a selection of buttons and indicators. At their centre you’ll find a numeric display showing the current reading from the Airsight Plus air quality sensor. This only detects PM2.5 particulates (those with a diameter of 2.5 microns or less), but it enables an auto mode, in which the Core 400S can step up its fan speed if the air quality declines.

Top panel view showing PM2.5 reading of 34
Image Credit (Trusted Reviews)

There are four manual fan speeds, but also Night Mode, in which the fan barely ticks over and the control panel lights are extinguished. You can also use the control panel to set an off timer in one-hour increments up to 12 hours, and there’s a lock function to stop others messing around with it.

This is a smart device, however. Install the VeSync app, use it to connect the Core 400S to your wireless network, and you’ll have access to more features, data and settings. Perhaps most importantly, VeSync lets you set schedules, so you can configure the Core 400S to fit in with the times you’re likely to be home.

Android screenshot from the VeSync app
Image Credit (Trusted Reviews)

The VeSync app shows up extra information, including historical air cleanliness and fan speeds. You can also use it to tweak the settings of Auto Mode, prioritising low noise, or tune it to the size of the room the filter is in. At its lowest, the fan will switch to the barely-on speed used in Night Mode, but unlike the more expensive Levoit Core 600S it won’t actually stop, even if the air quality is perfect.

Android screenshot from VeSync app, showing settings options
Image Credit (Trusted Reviews)

Before you can use this air purifier you’ll need to remove the plastic bag from its filter, which involves turning it upside down and removing the base. Ideally you’ll also do this every few weeks to vacuum off dust, which helps keep the filter working optimally. Levoit doesn’t state a fixed filter life as it depends on your home and how intensively you use the purifier, but it says you can expect replacements to last around 6-8 months. That means you’re likely to change filters once or twice a year, and at more than £60 a go that could be quite an expense.

The large filter, removed from the Core 400S
Image Credit (Trusted Reviews)


  • Very quiet and efficient
  • Fairly good filtration performance
  • Moderately powerful air circulation

This air purifier was quick to respond to deteriorating air quality, almost immediately stepping up the fan speed when I placed a lit-match a few centimetres from its sensor. It performed quite strongly in our more controlled smoke test, where I placed the purifier in a small room along with a smoke pellet that produces copious particulates for about 60 seconds. This test immediately sends an air purifier’s air quality meter off the scale.

It took the Core 400S five minutes to come down from its maximum 999μg/m3 reading, and a further four minutes before it returned to a moderate reading of 54 micrograms per cubic metre (μg/m3). After 10 minutes it reported good air quality, and one minute later this had become very good, with an 8μg/m3 reading. This is a decent performance, but it’s some way short of the more powerful Core 600S, which returned the air quality to very good within six minutes.

Top panel view, showing PM2.5 reading of 216
Image Credit (Trusted Reviews)

I use a second air quality meter to confirm the readings from any on-board sensor, but in this test I made the mistake of placing the burning pellet too close to the the Core 400S. The purifier’s powerful fan drew smoke from the pellet away from the second meter, so it returned lower-than-normal results.

My other tests confirmed that the Core 400S has an unusually powerful fan. Measured 15cm from the output, I recorded an air speed of 4.9 metres per second at full power, dropping to 1.2m/s at the lowest normal fan speed. Even one metre above, I measured 2.2m/s at full power – enough to stir up a noticeable draft in a medium-sized room.

Fortunately, this breeze isn’t accompanied by too much noise. From a metre away, I recorded only 25.2dBA in night mode – barely audible. This rose to a maximum of 42.7dBA on full power, which is just about enough that you’d need to raise your voice slightly. If you stick to speed three (39dBA) and below, you shouldn’t even need to do that.

This is an efficient air purifier, using just four watts in night mode, rising to 6W at speed one. This creeps up a little to 15W by the third speed setting, but even at full power I measured just 23W, which is excellent given it’s fairly powerful.

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Should you buy it?

A good air purifier for living spaces

With a powerful fan and decent filtration, this air purifier is well suited to living spaces in a decent-sized home. Its sensor means you could set and forget it, while the app means there are more settings and control available if you do need them.

Won’t suit every home

The Core 400S is overkill for smaller homes or rooms. Conversely, it’s not the most powerful air purifier around, and it misses out on UV sterilisation.

Final Thoughts

If you want an air purifier you can set and forget, the Core 400S might be a good choice. Its sensor doesn’t pick up volatile organic compounds, but it’s a useful addition that should ensure the purifier’s working hardest when the air’s most in need of being cleaned. With a powerful fan and decent performance against smoke, it’s up to the demands of reasonably big living areas, too.

I really like the VeSync app, which adds some useful features without being overly complicated. I’m also impressed by this purifier’s low noise and efficient running, even at high speed settings. That said, this purifier probably isn’t ideal for those with health conditions, who may benefit more from one with a germicidal UV lamp, such as the Leitz TruSens Z-3500H or something else from our guide to the best air purifiers.

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How we test

Unlike other sites, we test every air purifier we review thoroughly over an extended period of time. We use industry standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product.

Find out more about how we test in our ethics policy.

Used as our main air purifier for the review period

We test smart purifiers with their apps and we test Amazon Alexa and Google Assistant compatibility.

We time how long it takes each purifier to remove smoke from a closed room.


How long does the Levoit Core 400S filter last?

The filter life depends to an extent on how – and how much – you use the 400S, but each filter is likely to last around 6-8 months.

Does Levoit purifier remove mould?

A HEPA 13 air purifier like the Levoit Core 400S will remove mould spores from the air, which should prevent mould from growing or spreading. It won’t get rid of existing mould, however. If your home is prone to mould, it could be a sign you need to heat it to a warmer temperature, buy a dehumidifier, or simply ventilate it more – for example by opening a window.

Trusted Reviews test data

Time to clear smoke

Full specs

Quiet Mark Accredited
Size (Dimensions)
Release Date
First Reviewed Date
Voice Assistant
Smart assistants
App Control
Filter type
Max room size
Smoke CADR
Number of speeds
Auto mode
Filter replacement light

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